article: Kate is an American girl. Now she lives in New York with her parents. She lives in a community called Sunny Community. It's on Blue Street. There are five rows  of buildings in the community. Her house is in the first row. She lives on the third floor.
  There is a post office on Blue Street . Next to it ,there is a bank. Across from the bank ,there is a bookstore. The workers in the bookstore are very friendly to people. Mrs Green works in it. She is Kate's new neighbor. She has a son. His name is Bob. He is in the same class as Kate.
  Kate thinks the traffic here is very good, because she never meets any accidents here. She loves her community very much.
question: Who is Bob ?
options: Mrs Green's new neighbor. Kate's classmate. A worker in the bookstore. Kate's cousin.